void PieChartWidget::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    QPen pen;
    QRectF size;
    pen.setColor(Qt::black);
    pen.setWidth(2);
    painter.setPen(pen);

    if (this->height() > this->width())
    {
        size = QRectF(5,5,this->width()-10,this->width()-10);
    }
    else
    {
        size = QRectF(5,5,this->height()-5,this->height()-10);
    }

    double sum = 0.0,startAng =0.0;
    double angle,endAng;
    double percent;

    for(int i=0;i<qvValues.size();i++)
    {
        sum += qvValues[i];

    }
    for(int i=0;i<qvValues.size();i++)
    {
        percent = qvValues[i] / sum;
        angle = percent * 360.0;
        endAng = startAng + angle;
        painter.setBrush(qvColors[i]);
        painter.drawPie(size,static_cast<int>(startAng*16), static_cast<int>(angle*16));
        startAng = endAng;
        if(percent != 0)
        {
            painter.drawText(this->width()/4,this->height(), QString::number(percent*100)+"%");
        }

    }
}